Using the Hey3Met2 human ovarian cancer cell line, we previously found the RNASET2
gene to possess a remarkable in vivo tumor suppressor activity, although no in vitro
features such as inhibition of cell proliferation, clonogenic potential, impaired growth
in soft agar and increase in apoptotic rate could be detected. This is reminiscent of the
behavior of genes belonging to the class of tumor antagonizing genes (TAG) which act
mainly within the context of the microenvironment. Here we present transcriptional
profiles analysis which indicates that investigations of the mechanisms of TAG
biological functions require a comparison between the in vitro and in vivo expression
patterns. Indeed several genes displaying a biological function potentially related
to tumor suppression could not be validated by subsequent in vivo expression
analysis. On the other hand the fact that we could find congruency for three genes
both in vivo and in vitro adds a warning to a too much stringent categorization of
this class of genes which relies on the sensitivity of the methodological approaches.